Dual curable thiol-ene composition, comprising a polythiol, an unsaturated compound, a photoinitiator and an organic hydroperoxide, as well as a cross-linked polymer sealant prepared therefrom for use in aerospace

Abstract

A dual curable thiol-ene composition comprising a polythiol, an unsaturated compound, a photoinitiator, an organic hydroperoxide (thermal initiator) and optionally a nitrogen-containing base, such as e.g. an N-heterocyclic compound (together with the organic hydroperoxide a redox initiator system). A cross-linked polymer prepared therefrom. A method of making such a polymer. A cured sealant comprising such a polymer. The sealant is preferably for use in aerospace.

What is claimed is: 
     
       1. A composition comprising:
 a polythiol; 
 at least one unsaturated compound comprising more than one carbon-carbon double bond, carbon-carbon triple bond, or a combination thereof, wherein each carbon-carbon double bond or carbon-carbon triple bond is a terminal group; 
 a photoinitiator; 
 an organic hydroperoxide, and 
 a nitrogen-containing base comprising an imidazole or pyrazole. 
 
     
     
       2. The composition of  claim 1 , wherein the organic hydroperoxide comprises at least one of cumene hydroperoxide, tert-butyl hydroperoxide, or tert-amyl hydroperoxide. 
     
     
       3. The composition of  claim 1 , wherein the photoinitiator is a cleavage-type photoinitiator. 
     
     
       4. The composition of  claim 1 , wherein the polythiol is monomeric. 
     
     
       5. The composition of  claim 1 , wherein the polythiol is oligomeric or polymeric. 
     
     
       6. The composition of  claim 5 , wherein the polythiol is a polythioether oligomer or polymer or a polysulfide oligomer or polymer. 
     
     
       7. The composition of  claim 1 , wherein the at least one unsaturated compound comprises two carbon-carbon double bonds, and wherein the curable composition further comprises a second unsaturated compound comprising three carbon-carbon double bonds. 
     
     
       8. A method of making a polymer network, the method comprising:
 providing the composition of  claim 1 ; 
 and at least one of:
 exposing the composition to light to at least partially cure the composition; or 
 allowing the composition to at least partially cure at ambient temperature. 
 
 
     
     
       9. A polymer network preparable from the composition of  claim 1 , wherein at least some of the thiol groups in the polythiol and carbon-carbon double bonds, carbon-carbon triple bonds, or a combination thereof have reacted to form thioether groups. 
     
     
       10. A cured sealant comprising the polymer network of  claim 9 . 
     
     
       11. The composition of  claim 1 , wherein the organic hydroperoxide comprises at least one of cumene hydroperoxide, tert-butyl hydroperoxide, or tert-amyl hydroperoxide, the photoinitiator is a cleavage-type photoinitiator, the polythiol is monomeric, oligomeric or polymeric, and the at least one unsaturated compound comprises two carbon-carbon double bonds, and wherein the curable composition further comprises a second unsaturated compound comprising three carbon-carbon double bonds. 
     
     
       12. A composition comprising:
 a polythiol; 
 at least one unsaturated compound; 
 a photoinitiator; and 
 an organic hydroperoxide, 
 wherein either (a) the organic hydroperoxide is other than methyl ethyl ketone peroxide, or (b) the composition also comprises a nitrogen-containing ring and further wherein the at least one unsaturated compound comprises two carbon-carbon double bonds, wherein each carbon-carbon double bond is a terminal group, and wherein the curable composition further comprises a second unsaturated compound comprising three carbon-carbon double bonds. 
 
     
     
       13. The composition of  claim 12 , wherein the ring portion of the nitrogen-containing ring is unsubstituted or substituted with at least one halogen, alkyl, arylalkylenyl, or aryl. 
     
     
       14. The composition of  claim 13 , wherein the nitrogen-containing ring is an imidazole or pyrazole. 
     
     
       15. The composition of  claim 1 , wherein the ring portion of the nitrogen-containing ring is either unsubstituted or substituted with at least one halogen, alkyl, arylalkylenyl, or aryl. 
     
     
       16. The composition of  claim 1 , wherein each carbon-carbon double bond or carbon-carbon triple bond is a terminal group of a linear aliphatic compound. 
     
     
       17. The composition of  claim 12 , wherein each carbon-carbon double bond is a terminal group of a linear aliphatic compound.